The problem is that the c. heap doesn't heat up enough to kill the seeds. One solution is to not put the seed heads on the heap, especially those of foxgloves & alyssum, or any other prolific seeder. It's a pain cutting them off & composting the rest, but saves a lot of weeding. I don't know of a way to sterilise the compost, especially if you are putting it on your veg. plot. Someone else might know of a way though. At least you get plenty of plants for your ornamental garden, probably too many.

Your compost heap is not getting hot enough to kill off seeds - that requires a temperature of 130 degrees F for at least a week, and even then, tomato seeds may still be viable. This temperature is achievable using a hot composting method, but it requires regular turning and careful layering of materials. There is no other way of creating sterile, or at least seed and pathogen free, compost. Perhaps a change in how and what you compost might be useful - remove seed heads, flowerheads and fruits from green material before you add it to the compost heap. If your heap is not covered, cover it with something to try to exclude windblown seeds.

Ah, posted at the same time, sorry Feverfew!

My neighbour laughed when he saw me cutting seed heads off last year. He didn't now I'm the one laughing ;o))

As above, your heap does not get hot enough to kill the seeds. I also have this problem and so no longer spread the compost on the surface of the ground. Instead, I plan ahead and dig trenches where the different rows of veggies will go. I then put a layer of compost in the bottom of the trench and cover it over - not forgetting to mark the rows!

Good idea Bulba. I don't have a veggie plot , but I'm quite pleased with all the little Lobelia seeds that have come up everywhere & are now in bloom, helps fill in any gaps. Have thrown some Candytuft on the heap + seeds! don't mind where they come up.